One-to-One Associations

This article is relevant to entity models that utilize the deprecated Visual Studio integration of Telerik Data Access. The current documentation of the Data Access framework is available here.

This topic illustrates how to configure one-to-one associations. The workflow for defining one-to-one associations is the same as defining any normal one-to-many association. The only detail here is that, when the members(columns) selected for the source and target entity are Primary Keys, the created association is automatically created as one-to-one instead of one-to-many.

The following example demonstrates how to create an one-to-one association between the Customer and the CustomerDetail classes. If Customer and CustomerDetail are reference properties, the association created is automatically derived to be one-to-one. The only thing that should be paid attention to, is the IsRequired method call. IsRequired should be defined on the source end of the association so Telerik Data Access "knows" which side should be the source and which the target of the association. This is important because, when there is a constraint between the primary keys in the database, the record in the "target" table should be inserted first and the record in the source table should be inserted after that. Setting IsRequired on the correct side tells Telerik Data Access which side of the one-to-one association should be inserted first in the database. Sample FluentMetadataSource implementation could be found at the end of the topic.

customerConfiguration
   .HasAssociation(x => x.CustomerDetail)
   .WithOpposite(o => o.Customer)
   .HasConstraint((x, o) => x.CustomerId == o.CustDetailId)
   .IsRequired();

customerConfiguration.
    HasAssociation(Function(x) x.CustomerDetail).
    WithOpposite(Function(o) o.Customer).
    HasConstraint(Function(x, o) x.CustomerId = o.CustDetailId).
    IsRequired()

Customer

public class Customer
{
   public int CustomerId {get;set;}
   public string Name {get;set;}
   public string Type {get;set;}
   public CustomerDetail CustomerDetail {get;set;}
}

Public Class Customer
    Private _customerId As Integer
    Public Property CustomerId() As Integer
        Get
            Return Me._customerId
        End Get
        Set(ByVal value As Integer)
            Me._customerId = value
        End Set
    End Property

    Private _name As String
    Public Property Name() As String
        Get
            Return Me._name
        End Get
        Set(ByVal value As String)
            Me._name = value
        End Set
    End Property

    Private _type As String
    Public Property Type() As String
        Get
            Return Me._type
        End Get
        Set(ByVal value As String)
            Me._type = value
        End Set
    End Property

    Private _customerDetail As CustomerDetail
    Public Property CustomerDetail() As CustomerDetail
        Get
            Return Me._customerDetail
        End Get
        Set(ByVal value As CustomerDetail)
            Me._customerDetail = value
        End Set
    End Property
End Class

CustomerDetail

public class CustomerDetail
{
   public int CustDetailId {get;set;}
   public string Address {get;set;}
   public string Phone {get;set;}
   public Customer Customer {get;set;}
}

Public Class CustomerDetail
    Private _custDetailId As Integer
    Public Property CustDetailId() As Integer
        Get
            Return Me._custDetailId
        End Get
        Set(ByVal value As Integer)
            Me._custDetailId = value
        End Set
    End Property

    Private _address As String
    Public Property Address() As String
        Get
            Return Me._address
        End Get
        Set(ByVal value As String)
            Me._address = value
        End Set
    End Property

    Private _phone As String
    Public Property Phone() As String
        Get
            Return Me._phone
        End Get
        Set(ByVal value As String)
            Me._phone = value
        End Set
    End Property

    Private _customer As Customer
    Public Property Customer() As Customer
        Get
            Return Me._customer
        End Get
        Set(ByVal value As Customer)
            Me._customer = value
        End Set
    End Property
End Class

Sample FluentMetadataSource Implementation - One-To-One Association

public class FluentModelMetadataSource : FluentMetadataSource
{
   protected override IList<MappingConfiguration> PrepareMapping()
   {
       List<MappingConfiguration> configurations = new List<MappingConfiguration>();

       MappingConfiguration<Customer> customerConfiguration = new MappingConfiguration<Customer>();
       customerConfiguration.MapType( c => new
       {
           Id = c.CustomerId,
           Name = c.Name,
           Type = c.Type
       } ).ToTable( "Customers" );
       customerConfiguration.HasProperty( p => p.CustomerId ).IsIdentity( KeyGenerator.Autoinc );

       MappingConfiguration<CustomerDetail> customerDetailConfiguration = new MappingConfiguration<CustomerDetail>();
       customerDetailConfiguration.MapType( c => new
       {
           Id = c.CustDetailId,
           Name = c.Address,
           Type = c.Phone
       } ).ToTable( "CustomerDetails" );
       customerDetailConfiguration.HasProperty( p => p.CustDetailId ).IsIdentity();

       customerConfiguration
           .HasAssociation( x => x.CustomerDetail )
           .WithOpposite( o => o.Customer )
           .HasConstraint( ( x, o ) => x.CustomerId == o.CustDetailId )
           .IsRequired();

       configurations.Add( customerConfiguration );
       configurations.Add( customerDetailConfiguration );

       return configurations;
   }
}

Public Class FluentModelMetadataSource
    Inherits FluentMetadataSource
    Protected Overrides Function PrepareMapping() As IList(Of MappingConfiguration)
        Dim configurations As New List(Of MappingConfiguration)()

        Dim customerConfiguration As New MappingConfiguration(Of Customer)()
        customerConfiguration.MapType(Function(c) New With {
            Key .Id = c.CustomerId,
            Key .Name = c.Name,
            Key .Type = c.Type}).ToTable("Customers")
        customerConfiguration.HasProperty(Function(p) p.CustomerId).IsIdentity(KeyGenerator.Autoinc)
        customerConfiguration.FieldNamingRules.AddPrefix = "_"

        Dim customerDetailConfiguration As New MappingConfiguration(Of CustomerDetail)()
        customerDetailConfiguration.MapType(Function(c) New With {
            Key .Id = c.CustDetailId,
            Key .Name = c.Address,
            Key .Type = c.Phone}).ToTable("CustomerDetails")
        customerDetailConfiguration.HasProperty(Function(p) p.CustDetailId).IsIdentity()
        customerDetailConfiguration.FieldNamingRules.AddPrefix = "_"

        customerConfiguration.HasAssociation(Function(x) x.CustomerDetail).
            WithOpposite(Function(o) o.Customer).
            HasConstraint(Function(x, o) x.CustomerId = o.CustDetailId).IsRequired()

        configurations.Add(customerConfiguration)
        configurations.Add(customerDetailConfiguration)

        Return configurations
    End Function
End Class